1. Field of the Invention
The present invention relates to a gas supplying system and a gas supplying method, and more particularly relates to a gas supplying system and a gas supplying method which supply a reformed gas.
2. Description of the Related Art
Conventionally, a technique which uses a fuel cell as a distributed power source is known. For example, a cogeneration system is considered which uses a polymer electrolyte fuel cell (PEFC) and is jointly installed in a building, such as a typical house, a condominium and a building. In such a cogeneration, a case may be considered in which each of a plurality of PEFCs is distributed and placed for each house, room and floor. In this case, it is required that the individual PEFC is minimized and does not take a large space. To fulfill such requirements, integration of the sharable facilities in the plurality of PEFCs is an effective method.
As the sharable facility, a reformer for reforming a mixed raw material containing fuel and water and then generating a reformed gas can be exemplified. As a conventional method of supplying the reformed gas from the reformer to each of the plurality of PEFCs, a gas supplying method of a one-way traffic (non-circulation) is known. However, when the one-way traffic method is used to supply and distribute the reformed gas, there is a possibility that the water component in the reformed gas is condensed into the pipes of the fuel cell having no demand for the reformed gas in a certain period. A technique for avoiding the blockage and corrosion of the pipes by the water condensation is desired.
When the reformed gas is supplied to each of the plurality of PEFCs, it is important to prevent the supply quantity to all of the PEFCs from being short, irrespectively of the increase or decrease in the usage quantity of the reformed gas in each PEFC. Thus, a technique that makes supply of the reformed gas stable is desired.
As a related technique, Japanese Laid Open Patent Application (JP-A 2003-28449) discloses a system and method for supplying the energy to a community. This system uses an energy generating facility as a core and supplies the generated energy to the houses of the inhabitants in the community. This system includes an energy supply route, an information communication line, a use situation detector, and a managing unit. The energy supply route connects an energy generating facility and the houses of the inhabitants. The information communication line is laid along the energy supply route. The use situation detector is installed for each house and connected to the information communication line and detects the energy use situation in each house. The managing unit collects the detection output from the use situation detector in each house through the information communication line, and levels the usages of the energies in the respective houses, and manages that the usage quantity of the energy in the entire community does not exceed a preset standard.
As the related technique, Japanese Laid Open Patent Application (JP-A 2002-281568) discloses a cogeneration system. This cogeneration system jointly uses the commercial electric power supplied from an electric power company and the electric power generated by a distributed electricity generation apparatus, and on the other hand, uses the waste heat from the dispersed electricity generation apparatus for hot water supply. This has the dispersed electricity generation apparatus, an electric power controller, a gas controller, a warm water storage bath and a system controller. The dispersed electricity generation apparatus uses the gas supplied from a gas company as an energy source. The electric power controller controls the supplies of the electric powers from the dispersed electricity generation apparatus and the commercial electric power. The gas controller controls the supply of the gas from the gas company. The warm water storage bath stores the warm water obtained from the waste heat from the dispersed electricity generation apparatus. The system controller controls the dispersed electricity generation apparatus, the electric power controller and the gas controller.
As the related technique, Japanese Laid Open Patent Application (JP-A-Heisei, 8-308587) discloses a hydrogen supplying facility and a cogeneration system facility. This hydrogen supplying facility includes a culturing unit (7), a culturing temperature keeping mechanism (8) and an organic matter supplying mechanism (18). This culturing unit (7) cultures a hydrogen generation super thermophilic bacteria that generates hydrogen, which is cultured with an organic matter as nutrition, in anaerobic atmosphere having a temperature higher than a room temperature. The culturing temperature keeping mechanism (8) is heated by a waste heat holding medium of 80 degrees centigrade or more, which is exhausted from a waste heat source, and keeps the culturing unit (7) at the temperature suitable for the proliferation of the hydrogen generation super thermophilic bacteria. The organic matter supplying mechanism (18) supplies the organic material required to proliferate the hydrogen generation super thermophilic bacteria into the culturing unit (7). This is designed so as to include a hydrogen storage vessel (14) for extracting the hydrogen generated in the culturing unit (7) with the proliferation of the hydrogen generation super thermophilic bacteria, from the culturing unit (7) and storing therein and so as to enable the hydrogen from being extracted from the hydrogen storage vessel (14).
To achieve high efficiency, various types of cogeneration systems including the fuel cell are considered. As a cogeneration system for supplying the electricity from electricity generation and the heat using waste heat, a system is developed for using an engine or turbine. This system uses the conventional machine whose research has been almost completed. Thus, the durability of an apparatus is excellent, and the facility cost is cheap. Also, a system that has a controller to follow a severe load variation in order to apply to a typical house where a demand for an electric power is greatly varied between day and night is disclosed in Japanese Laid Open Patent Application (JP-A2001-112176).
Also, as the cogeneration system, a system is developed which uses a phosphoric acid fuel cell (PAFC) or a polymer electrolyte fuel cell (PEFC). As for the PAFC, in a case of a continuous operation, the electricity generation efficiency is high such as approximately 40%. However, since the operation temperature is high such as 200 degrees centigrade, trying to carry out a DSS operation for repeating a startup and a shutdown brings about the big drop in performance. On the contrary, the operation temperature of the PEFC is low such as 70 degrees centigrade. Thus, the times necessary for the startup and the shutdown are short. Hence, even in the DSS operation, it is possible to attain the high electricity generation efficiency. Also, a heat storage tank for storing the waste heat of the PEFC in order to enable the use of hot water supply even after the stop of the PEFC operation is disclosed in Japanese Laid Open Patent Application (JP-A 2002-289212) and Japanese Laid Open Patent Application (JP-A 2002-333207).